The present invention relates to a compact motor. More specifically, the present invention relates to an attachment structure for C-shaped magnets for a compact motor.
Referring to FIG. 3, there is shown a well known technology for compact motors. A C-shaped magnet B, which has opposing poles along its circumference, is positioned inside a motor case A. Motor case A is press-formed in the shape of a cup. A rotor D is attached to a shaft C inside C-shaped magnet B.
A pair of bearings E1, E2 rotatably support shaft C between an end wall of motor case A and a bracket F. Bracket F covers an open portion of motor case A. A star-shaped layered core G, an excitation coil H, and a commutator I are supported at an intermediate portion of shaft C.
Brushes J are supported by an insulative resin mold K inside bracket F. Ends j of brushes J form a sliding contact with commutator I. Brushes J are electrically connected to leads L which extend outside motor case A.
The conventional method for fixing C-shaped magnet B to motor case A has involved aligning a notch M formed on C-shaped magnet B with an embossed projection N formed on motor case A. With the rotational position of C-shaped magnet B relative to motor case A defined in this manner, C-shaped magnet B is fixed to the inner surface of motor case A using an adhesive.
However, in this fixing structure for C-shaped magnet B, the use of adhesive complicates the assembly process. The adhesive may peel off later and make the positioning of C-shaped magnet B unstable. In particular, when a plurality of C-shaped magnets are to be attached inside a compact motor, the peeling off of adhesive can lead later to critical problems. Thus, accurately fixing a plurality of C-shaped magnets to prescribed positions has been difficult.